Digital display indicator

ABSTRACT

A digital display indicator wherein a vertically movable shutter having horizontal segments formed thereon, and a horizontally movable shutter having vertical segments formed thereon are selectively positioned with respect to each other, and to a slotted member in the form of a figure 8 for selectively displaying numerals from 0 thru 9.

United States Patent Boyles [54] DIGITAL DISPLAY INDICATOR [72] Inventor: Robert L. Boyles, Wayland, Mass.

[73] Assignee: General Electric Company [22] Filed: Jan. '12, 1971 [21 Appl. No.: 105,854

52 us. c1. ..40/'2s c 511 1m. (:1 .0091 11/00 581 Field 6: Search ..40/28, 28 c, 52, 130 E [56] I References Cited UNITED STATES PATENTS 2,426,079 8/l947 Bliss ..40/2s c 3,096,594 7/1963 Skrobisch ..40/2s c 3,174,144 3/1965 Oneill ..340/324 3,249,932 5/1966 Sklaroff ..340/37s 3,261,013 7/1966 Naylor ..40/2s c x 1451 Aug. 15, 1972 3,363,347 l/ 1968 Benson ..40/28 C 3,399,474 9/1968 Rinder ..40/28 C 3,405,464 10/ 1968 Simson ..40/28 C 3,467,960 9/ 1969 l-losker ..340/ 378 Primary ExaminerRobert W. Michell Assistant Examiner-Wenceslao J. Contreras Attorney-Lawrence R. Kempton, Leonard J, Platt, John F. Cullen, Frank L. Neuhauser, Oscar B. Waddell and Joseph B. Forman ABSTRACT A digital display indicator wherein a vertically movable shutter having horizontal segments formed thereon, and a horizontally movable shutter having vertical segments formed thereon are selectively positioned with respect to each other, and to a slotted member in the form of a figure 8 for selectively displaying numerals from 0 thru 9.

18 Clains, 10 Drawing Figures Patented Aug. 15,1972 3,683,523

3 Sheets-Sheet l Mueniafl fake/i L, figy/es Altar/2g Patented Aug. 15, 1972 3,683,523

3 Sheets-Sheet 8 BACKGROUND OF THE INVENTION This invention relates to a digital display indicator, and more particularly to a display indicator having a plurality of horizontal and vertical segments arranged in the shape of a numeral 8 for indicating numerals from thru 9.

As is well known in the digital display art, numerals from 0 thru 9 may be readily formed from seven straight-line indicator segments or bars which are arranged in the shape of a FIG. figure 8. The seven indicator bar segments include three generally parallel horizontally arranged bars and two pairs of generally vertically arranged bars positioned on opposite sides of the horizontal bars. With this arrangement, should it be desired to display a numeral 1, all bar segments except the two right vertical segments would be blocked out. To form the numeral 0, it is only necessary to block out the middle horizontal bar. It follows that the numeral 3 may be formed by blocking out the two left vertical bars.

The prior art includes many different constructions and arrangements for blocking out or lighting the desired indicator bar segments. Shutters having light reflective surfaces formed on them have been selectively moved behind seven bar slots arranged in the shape of a FIG. 8 for forming the numerals, and various other mechanical and electrical arrangements have been utilized for blocking out or lighting the desired indicator segments or slots. These prior art constructions have included a large number of components for selectively blocking out or lighting the indicator slots or segments. For example, in one prior art construction as shown in a prior US. Pat. No. 3,399,474 to Rinder dated Sept. 3, 1968, four sliders positioned behind a slotted aperture plate are required for forming the numerals from 0 thru In another prior art construction as shown in a US. Pat. to Skrobisch No. 3,096,594, there is disclosed a numeral readout device which also includes a sevenbar slotted plate with the indicator bars arranged in the shape of a FIG. 8; however, in place of slides behind the FIG. 8, a plurality of magnetically rotated drums having flags formedthereon are positioned behind each of the seven-bar slots. With such a construction seven separate motors are required for rotating the drums to move the flags into or out of position behind the slotted FIG. 8 plate.

This invention is concerned with such seven indicator bar numeral readout devices with the bars arranged in the shape of a FIG. 8, and more particularily to a unique construction for displaying the appropriate indicator segments.

Accordingly, it is a primary object of my invention to provide an improved digital display indicator for displaying numerals 0 thru 9 which may be reliably and quickly changed from one numeral to the next succeeding numeral.

It is a further object of my invention to provide an improved digital display indicator having a minimum number of parts which may be readily manufactured and assembled to each other.

SUMMARY OF THE INVENTION In accordance with one of the aspects of this invention, a numeral display indicator includes a member having a plurality of indicator bars formed therein arranged in the shape of a figure 8. There are three generally parallel horizontal bars and two pairs of generally vertical bars positioned on opposite sides of the horizontal bars. Two movable shutters are positioned adjacent to the FIG. 8 member for selectively blocking out selected indicator bars in order to display numerals 0 thru of the shutters includes a plurality of generally horizontal opaque bars for selectively blocking out one or more of the horizontal indicator bars formed in the FIG. and the other shutter includes a plurality of generally vertical opaque bars for selectively blocking out the vertical segments of the member. The shutter with the horizontal bars is arranged to be slid up and down vertically behind the member while the shutter with the vertical bars is arranged to be slid in a horizontal direction behind the FIG. 8 member. By this arrangement, all of the numerals from 0 thru 9 can I be readily formed by moving only two shutters. A suffi- FIG. 8 member to form all of the numerals from 0 thru 9.

BRIEF DESCRIPTION OF THE DRAWING Other objects and attendant advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing in which:

FIG. 1 is an exploded perspective view of a digital display indicator constructed in accordance with my inventlon;

FIG. 2 is a fragmentary front elevational view of the vertically movable shutter and a portion of the shutter actuating mechanism for the digital display indicator shown in FIG. 1;

FIG. 3 is a fragmentary front elevational view of the horizontally movable shutter and a portion of the shutter actuating mechanism of the digital display indicator shown in FIG. 1;

FIG. 4 is a side elevational view of the digital display indicator shown in FIG. 1;

FIG. 5 is a diagrammatic view showing the vertically movable Y shutter and the slotted block FIG. 8 member of the display indicator shown in FIG. 1, with the shutter shown in its E position wherein the upper and lower horizontal bar slots of the member are blocked out and the central slot of the member is not blocked out so that it may cooperate with appropriate vertical slots to form a numeral 4;

FIG. 6 is a diagrammatic view of the slotted numeral 8 member along with the horizontally movable X shutter of the display indicator shown in FIG. 1, the X shutter being shown in its l-I position wherein the lower left vertical slot of the numeral 8 member is blocked out and the other vertical segments are not blocked out so that the clear unblocked out vertical segments may cooperate with the central clear horizontal segment to form a number 4;

FIG. 7 is a diagrammatic view of the slotted FIG. 8 member and portions of the X" shutter .and the Y shutter with the parts in the positions illustrated in FIGS. 5 and 6 to form a numeral 4;

FIG. 8 is a chart showing the relative positions of the X" and Y" shutters for forming the numerals from thru 9. It can be seen that in order to form the numeral 4 shown in FIG. 7, the Y shutter is in its E" position shown in FIG. while the X shutter is in its H position shown in FIG. 6;

FIG. 9 is a diagrammatic front view of the control cam for operating the X" and Y shutters, the view showing the Y" cam groove in its C-9 position to display a numeral 9; and

FIG. 10 is a diagrammatic front view of the cam for actuating the vertical and horizontal shutters shown in FIG. 1, the view showing the X" cam groove and the X" cam follower pin in their II-9 position for displaying a numeral 9.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, and first particularily to FIG. 1, there is shown an exploded perspective view of my unique digital display indicator. The display indicator includes a front plate 2 which may be formed of a clear plastic or glass material suitably blocked out by painting to reveal a clear numeral 8 unobstructed by blocked out portions at the corners of the numeral 8. As illustrated in FIG. 1, the display indicator may also be formed of an opaque plastic or other material which may be readily slotted to form a numeral 8. The numeral 8 member includes seven indicator bar slots which are utilized for forming the numbers from 0 thru 9. There are three generally horizontal indicator bar slots, 6, 7 and 10, and four generally vertical indicator bar slots 12, 14, 16 and 18 positioned on opposite sides of the horizontal bars.

According to my invention a vertically movable shutter 26 with horizontal bars is slidably positioned behind the slotted bar numeral 8 member for selectively blocking out one or more of the horizontal indicator bars 6, 7 and 10. It can be appreciated that all of the horizontal bars should be blocked out for displaying a numeral 1 while only the central bar 7 should be blocked out for displaying the numeral 0. It follows that all of the horizontal bars should be clear or unobstructed in order to display the numeral 3. To achieve this, a plurality of opaque shutter bars 30, 32, 34, 36, 38 and 40 may be painted or otherwise formed on the vertically movable shutter member 26 for blocking out the appropriate horizontal indicator bars. The shutter may be formed of a relatively thin transparent plastic material, and with such a construction light which emanates from a lamp 41 or other suitable light source positioned behind the shutter flows through the clear portions 42, 44, 46, 48 and 50 of the shutter and thence through any unobstructed generally horizontal bars 6, 7 and 10 of the slotted numeral 8.

A horizontally slidable shutter is positioned behind the vertically slidable shutter for selectively obstructing the vertical bars 12, I4, 16 and 18 of the slotted FIG. 8. It can be appreciated that the upper left vertical bar 12 should be blocked out to display numerals l, 2 and 3 while it would be unobstructed to display the numerals 6, 8 and 9, for example. The horizontally slidable shutter is preferably formed of the same material as the vertically slidable shutter and it includes a plurality of vertical opaque bars 62, 64, 66, 68, 70 and 72 for blocking out the vertical indicator bars 12, 14, 16 and 18 of the FIG. 8 indicator member. It can be seen that the opaque shutter bar 62 is provided for blocking out the indicator bar 14 of the FIG. 8 member, shutter bar 68 blocks out indicator bar 18 while the remaining shutter bars 64, 66, 70 and 72 are provided for blocking out the left vertical indicator bars 12 and 16. The horizontally slidable shutter 60 includes transparent portions 63 between the shutter bars for enabling light from a lamp 41 to flow through the transparent portions to thereby visually display the vertical indicator bars 12, I4, 16 and 18. In like manner, the vertically slidable shutter 26 includes transparent portions 42 between the opaque shutter bars 30, 32, 34, 36, 38 and 41 for lighting the horizontal indicator bars 6, 7 and 10 by light which may flow from lamp 40 through horizontal transparent portions 65 of the horizontally slidable shutter 60 and then through the clear portions of the vertically slidable shutter 26.

In the absence of a light source 41, it can be appreciated that the clear portions between the opaque shutter bars 30, 32, 34, 36, 38, 40, 62, 64, 66, 68, and 72 may be colored white, red or other distinct colors to enable the painted color to be viewed through the indicator bar slots, 6, 7, 10, 12, 14, 16 and 18 depending on the relative positions of the vertically movable shutter 26 and the horizontally movable shutter 60.

It can be readily appreciated that in order to display a particular numeral, the vertical shutter bar has to be moved to one position while the horizontally movable shutter bar is required to be moved to a different position. For example, in order to display the numeral 4, as shown in FIG. 7, the vertically movable shutter has to be moved to block out the horizontal indicator bars 6 and 10 while leaving the central bar 7 clear. In a similar manner, the horizontally movable shutter 50 has to be moved to block out only the lower left vertical indicator bar 16. The remaining vertical indicator bars 12, 14 and 18 have to be left open in order to display the numeral 4. To achieve this, in accordance with my invention the vertical shutter bars 30, 32, 34, 36, 38 and 40 are positioned as shown in FIG. 5.

The number, relative position and width of the opaque shutter bars 30, 32, 34, 36, 38, 40, 62, 64, 66, 68, 70 and 72 which are formed or printed on the shutters 26 and 60 are uniquely selected in accordance with my invention in order to require only small incremental movements of the horizontal and vertical shutters for shifting from one numeral to a succeeding numeral. Moreover, the shape of the numerals are also selected to some degree to minimize the number of opaque bars which are required and also to reduce the incremental excursions of the horizontal and vertical shutters in changing from one number to the next. With particular reference to FIG. 8, it can be seen that the numeral 6 includes an upper horizontal bar while numeral 9 includes a lower horizontal bar. Thus, all three horizontal indicator bars 6, 7 and are required for forming numerals 2, 3, 5, 6, 8, and 9, and with this selection the vertically movable shutter 26 is moved to one position for displaying all of these numerals.

My unique shutter bar arrangement which requires only small incremental movements of the horizontal and vertical shutters for shifting from one numeral to a succeeding numeral is graphically illustrated in FIGS. 5, 6, 7 and 8. FIG. 8 is a chart showing the relative positions of the X and Y shutters for forming the numerals from 0 thru 9. It can be seen that in order to form the numeral 4 shown in FIG. 7, the Y shutter is placed in its E position shown in FIG. 5 while the X shutter is placed in its H position shown in FIG. 6. The various positions of the Y shutter are illustrated at the lower part of FIG. 5, and as shown, in the E position opaque shutter bars 40 and 32 block out the upper and lower indicator slots 6 and 10.

With reference to FIG. 5, when the shutter 26 is moved downwardly one increment to its D position, the relatively large lower opaque bar 40 will continue to cover the lower indicator bar slot 10, intermediate opaque bar 36 will be moved downwardly to cover the central horizontal bar 7, and the opaque bar 32 will be moved downwardly far enough so that it will not register with the upper indicator bar 6. Thus, the clear portion 42 of the Y shutter will be in register with the upper indicator bar slot 6 and the Y shutter will be in a position to display a numeral 7. With particular reference to FIG. 8, it can be seen that in order to display a numeral 7 the Y slider is placed in its D position.

A similar diagrammatic illustration'is also provided for showing the different positions of the X shutter. As shown in FIG. 6, the X shutter is in its H position or its second position from its right most G position. In the H position illustrated, it can be seen that the lower left opaque bar 72 blocks out the lower left indicator bar 16. The remaining opaque shutter bars are positioned to unobstruct the indicator bar slots 12, 14 and 18. With particular reference to FIG. 8, it can be seen that when the X shutter is placed in its I-I position it is in a position for displaying either a numeral 4 or a numeral 9. When the X shutter is moved an additional increment to the left to its K position, it is in a position for displaying the numeral 2 as indicated in FIG. 8.

With particular reference to the code sheet shown in FIG. 8 and the diagrammatic view of FIG. 5, it can be readily perceived that the vertical shutter bar is moved to its C position for displaying all of the numerals, 2, 3, 5, 6, 8 and 9. It can also be seen that the other four numerals require separate positions. However, as shown in FIG. 5, the separate positions for the other numerals are disposed with respect to the C position so that the C position is the middle. Accordingly, it is never necessary to move the shutter bar through more than one position to get to the next succeeding numeral. In other words, after the vertical shutter 26 has displayed the numeral 3 and it is necessary to move the shutter from the C position to the E position to display the numeral 4, the shutter bar only has to be moved upwardly from the C position through the D position to the E position. In order to get to numeral 6 the Y shutter has to move back to the C position through the E position. It can therefore be seen that the C position of the vertical shutter bar for displaying the numerals 2, 3, 5, 6, 8 and 9 is rather significant. It is centrally positioned between the other positions so that it is only necessary to move the shutter through one position to obtain the necessary succeeding numerals. Moreover, in changing from numeral 2 to 3 and from numeral 5 to 6 and from 8 and 9, it is not necessary to move the shutter at all. Thus, a unique shutter bar configuration has been provided so that the Y shutter only has to be moved small incremental amounts for changing from one number to a succeeding number.

The opaque bars on the horizontally movable shutter are also uniquely selected in regard to thickness and relative disposition with respect to each other so that relatively few separate positions are required for displaying numbers from 0 thru 9, and only incremental excursions of the horizontally slidable X shutter are required for moving from one number to the next succeeding number. As shown more particularily in FIGS. 6 and 8, six separate positions identified by the letters G, H, K, M, P and R are required. With particular reference to FIG. 8, numerals 0 and 8 are formed when the X shutter is in its M position, two numerals 9 and 4 are formed with the X shutter in its I-I position, and three numerals l, 3 and 7 are formed with the X slider in its G position. While the X shutter has to be moved a greater amount for moving from one succeeding number to the next number than the Y shutter, it can be appreciated that the Y shutter is only required to block out three horizontal indicator bars while the X shutter is required for blocking out two pairs of vertical indicator bars. Nevertheless, the greatest movement is required in moving from the H position for displaying the numeral 4 to the R position to display a numeral 5.

In accordance with my object to reduce to a minimum the number of parts required for my digital display indicator, I have designed a uniquely shaped two-faced rotatable cam for moving the X and Y shutters to the positions indicated in FIGS. 5 and 6. The front face 82 of the cam includes a cam groove 84 for receiving a cam follower 86. As shown more particularily in FIG. 1, the cam follower 86 may be integrally formed on a lever 88 which is connected at one end to the vertically movable shutter by means of a pivot 90 formed on the lever and a slot 92 integrally formed in the lower portion of the vertical shutter 26. The other end of the lever may be suitably connected to the front plate 2 of the display indicator by means of a pivot which is fixed to the front plate and extends through an aperture 91 in the lever 88. With this construction, it can be appreciated that rotation of the cam 80 in a clockwise direction as shown in FIGS. 1, 2 and 9 will cause the cam follower 86 to move radially inwardly or outwardly with respect to the cam to thereby cause corresponding upward or downward movement of the vertical shutter 26 to the positions indicated in FIGS. 5, 8 and 9. With the cam rotated to the position illustrated in FIG. 9, the cam follower 86 is moved to one of the C positions listed in FIG. 8 wherein the follower is positioned in a portion of the cam track groove 84 which is about midway between the periphery and the hub of the cam. In this position, all of the horizontal indicator bars will be open to display one of the numerals 2, 3, 5, 6, 8 or 9; however, in the position illustrated, the cam track 100 on the opposite side of the cam will move the vertical bar shutter so that the numeral 9 is displayed.

With particular reference to FIGS. 3, 4 and 10, cam groove 100 is formed on the rear face of the rotatable cam 80 for moving the X shutter 60 back and forth behind the vertical shutter 26 and the slotted numeral 8. As shown, a cam follower 102 which is formed on a lever 104 is positioned within the X cam track on the rear surface of the cam 82. The lever 104 is preferably mounted on my display indicator by means of a pivot 106 which may be staked or otherwise fixed to a rear plate 108. A slot 1 10 is formed in one of the arms of the lever 104 for receiving a rearwardly extending lug 112 which may be integrally formed on the horizontal shutter 60. With this construction, when the cam is rotated in the clockwise direction illustrated in FIGS. 1, 2, 9 and 10, the front cam groove and cam follower causes the vertical slider to move upwardly and downwardly with respect to the numeral 8 member, and the rear cam track 100 causes the cam follower 102 and lever 104 to move the horizontal shutter to the right and left behind the vertical shutter and the slotted numeral 8.

The cam track 84 on the front surface of the cam 80 is uniquely related to the X cam track 100 on the rear surface of the cam so that when the Y front cam track is in the position illustrated in FIG. 9, the X cam track is located in the position illustrated in FIG. 10 and both of the cam tracks cooperate to move the horizontal and vertical shutters to display the numeral 9. In these positions, with particular reference to FIG. 8, it can be appreciated that the Y cam track and Y slide are in the C position while the X cam track and cam follower are in the H position to display a numeral 9. In the H position illustrated in FIG. 6, the X shutter blocks out the lower left indicator bar, and in the C position the Y shutter leaves all of the horizontal bars open, and thus a numeral 9 is displayed.

When the cam 80 is moved clockwise in the direction of the arrows from the position illustrated in FIGS. 9 and 10, the Y cam groove will move the cam follower 86 radially inwardly to its B- position for moving the Y slider to the B position to block out the middle horizontal bar 7 and open the upper and lower horizontal bars 6 and 10 to display the numeral 0. At the same time, the rear cam track 100 is moved clockwise to move the cam follower 102 radially inwardly from its H-9 position to its M-O position to thereby move the X shutter to the left as shown in FIG. 6 from its H position to its M position to thereby open all of the vertical indicator bars to display the numeral 0. Continued rotation of the cam 80 in the clockwise direction illustrated by the arrows will move the horizontal and vertical cams successively to the numeral 1, numeral 2, and numeral 3 positions, etc. The positions of the cam followers in the X and Y tracks for moving the shutters to display a particular numeral are shown in circle dotted lines in FIGS. 9 and 10 and are identified by reference letters and numerals. For example, in FIG. 9 the reference letters and numerals A1, C-2 and C-3 appear while in FIG. 10 the reference letters and numerals H-9, M-O, G-1 and K-2 appear. The suffix numeral corresponds to the numeral which will be displayed when the cam follower is moved to the identified portion of the cam track while the prefix letter identifies the various letter positions of the X and Y shutters illustrated in FIGS. 5 and 6, and listed in the chart FIG. 8.

From the foregoing discussion, it can be appreciated that the horizontal and vertical shutters 60 and 26 are uniquely related to each other and to the cam tracks 84 and which are formed on the front and rear surfaces of the cam 80. It is very significant that the shutter bars have been arranged so that relatively small incremental movements of the shutters are required for moving from one numeral to a next succeeding numeral. In this way, 360 of rotatable cam surfaces is all that is required for forming all of the numerals from 0 thru 9. Moreover, with the small incremental movements required, the cam may be formed of relatively inexpensive plastic, and the cam follower members 86 and 102 may also be formed of a relatively inexpensive plastic material since the slope of the cam tracks does not have to be too steep.

As indicated hereinbefore, the greatest movement required for either shutter is the movement required of the horizontally slidable shutter 60 in moving from its H position for displaying the numeral 4 to its R position for displaying the numeral 5. With reference to FIGS. 6 and 8, it can be appreciated that in such a movement the horizontally movable shutter is moved through three positions K, M and P. With reference to FIG. 10, it can be seen that the slope of the cam track 100 is greatest in that area of the cam where the follower is moved from its H4 to its H5 position, and angle 101 indicates the slope of the cam track 100 in moving from its H4 to its R5 position. The angle as shown is approximately 60 and the slope is not too steep to be traversed by the plastic cam follower 102 operating in a plastic cam groove 100.

In addition, the slopes of the cam tracks 84 and 100 are not so steep as to require a high torque motor. A conventional clock motor having a usual torque output of 0.3 lb.in. at l rpm is sufficient for moving the cam 80 to move the cam follower 102 from its H4 to its R5 position. In this connection it can be appreciated that when the X cam follower 102 is moved from its H4 position to its R5 position, the cam follower 86 for the Y shutter is moved from its E4 position to its C5 position. In this instance, the Y cam slide is only required to move through one position D in moving from its E4 position to its C5 position. Therefore, at the time that substantial motor torque may be required for moving the X cam follower 102 from its H4 position to its R5 position, relatively little torque is required for moving the Y cam follower 86 from its E4 position to its C5 position. It is therefore significant that the Y cam slide has been designed so that very small increment excursions are required for moving from one numeral to a next succeeding numeral.

In order to complete the assembly of the digital display indicator, suitable guideways may be provided on the front plate, and the vertical and horizontal shutters may be suitably sandwiched between the front plate 2 and a transparent guide plate which may be conveniently held to the front plate by guide tabs 122 which extend rearwardly from the front plate and into the notches which are formed at the corners of the guide plate 120. A slot may be formed in the guide plate 120 for receiving the rearwardly extending lug 112 which is integrally formed on the horizontally slidable shutter. Spacer posts 146 and 148 are positioned between the front plate and the rear plate 106 and suitable screws 150 may extend through apertures formed in the front plate for connecting the front plate to the spacer posts 146 and 148.

In the embodiment illustrated, the cam 80 may be mechanically rotated by a knob 160 which may be integrally formed with the cam. As shown in FIGS. 1 and 4, the knob 160 extends through an aperture 162 formed in the front plate, and a suitable indicating pointer 166 may be connected to the knob for cooperation with a dial plate 164 which may be fixed to the front plate in the vicinity in the protruding mechanically rotatable knob 160 so that a person rotating the knob may readily observe the numerals which are being displayed and which may be displayed by my unique display indicator. While such a dial 164 is not required in the embodiment illustrated since rotation of the knob 160 will cause a particular numeral to be displayed by the slotted bar FIG. 8 member, it can be appreciated that in a large display indicator such as those used for displaying scores at a ball game the apparatus for rotating the knob 160 or the cam 80 may be remotely positioned so that the person moving the cam may not be able to observe the slotted FIG. 8 display. It is also contemplated that electric motor means may be utilized for rotating the cam 80 in a forward or a reverse direction in order to display different numerals, and a synchronous electric motor may be connected to the cam 80 for displaying time.

From the foregoing description, it will be appreciated that my improved digital display mechanism is achieved with the use of a minimum number of parts which are uniquely connected to each other and combined with each other for displaying desired numerals from thru 9. Moreover, the opaque bars on the horizontally slidable and vertically slidable shutters are uniquely spaced and positioned to minimize the incremental excursions in changing from one numeral to the next. A rotatable cam 80 having a front cam track 84 and a rear cam track 100 is all that is required for moving the vertical and horizontal shutters. Thus, an ex ceedingly simple, yet reliable digital display indicator has been achieved.

What I claim is:

l. A digital indicator for visually displaying numerals 0 thru 9 comprising:

a. an indicator member having a plurality of indicator bars provided therein arranged in the shape of a figure 8, said indicator bars including three generally parallel horizontal bars, and two pairs of vertical bars on opposite sides of the horizontal bars:

b. two movable shutters positioned adjacent to the indicator bars of said figure 8 member for selectively blocking out selected bars in order to selectively display numerals 0 thru 9;

one of said shutters including a plurality of generally horizontal opaque bars for selectively blocking out one or more of the three generally horizontal indicator bars, said horizontal bar shutter being arranged for movement up and down in a generally vertical direction behind said figure 8 member; and

d. the other shutter including a plurality of generally vertical opaque bars for selectively blocking out one or more of the vertical indicator bars which are positioned on opposite sides of the horizontal bars, said generally vertical bar shutter being arranged for movement in a generally horizontal direction behind said figure 8 member.

2. A digital numeral display indicator as defined in claim 1 wherein the horizontal and vertical indicator 0 bar portions are formed as slots in an opaque plate with the slots extending through the plate from one side of the plate to the other side of the plate.

3. A digital indicator as defined in claim 1 including:

a. guide means for permitting slidable movement of said horizontal bar shutter in a generally vertical direction;

b. guide means for permitting movement of said vertical bar shutter in a generally horizontal direction;

c. a first lever operatively connected to said vertically movable shutter for moving the shutter;

d. a second lever operatively connected to said horizontally movable shutter for moving the shutter;

e. a rotatable cam having a front face and a rear face;

f. a cam follower formed on said first lever for moving said vertically movable shutter;

g. a cam follower formed on said second lever for moving said horizontally movable shutter; and

h. cam tracks formed in the front and rear surfaces of said rotatable cam, one of the cam followers being positioned in one of the tracks for moving the horizontal shutter and the other cam follower being positioned in the other track for moving the vertical shutter, the cam track in the front surface of the cam being so related to the cam track in the rear surface of the cam so that in any one of a plurality of selected positions of said cam, the cam tracks and cam followers position the horizontal and vertical shutters to block out the appropriate indicator segments to display a numeral from 0 thru 9.

4. A digital display indicator as set forth in claim 3 wherein the cam follower on the lever which is operatively connected to the horizontal bar shutter is positioned in the cam track formed on the front surface of the cam and the cam follower on the lever which is operatively connected to the vertical bar shutter is positioned in the track formed in the rear surface of the cam.

5. A digital indicator as defined in claim 3 wherein the cam followers and the rotatable cam are formed of plastic material and the slope of the cam tracks vary from 0 thru 60.

6. A digital display indicator as defined in claim 1 wherein the shutters are made of a relatively thin transparent material, the opaque shutter bars are formed on the shutters, and a light source is positioned behind the shutters and the indicator bar member for illuminating the bars in the indicator member which are not blocked out by the shutters.

7. A digital indicator as defined in claim 1 wherein the shutter with the vertical bars includes an enlarged vertical bar at its lower left portion for blocking out the lower left indicator bar in the indicator member for displaying numerals l, 3, 4, 7 and 9.

8. A digital indicator as defined in claim 7 wherein a vertical opaque bar is positioned inwardly from the vertical bar at the lower left portion of the shutter for blocking out the lower left indicator bar for displaying the numeral 5.

9. A digital indicator as defined in claim 1 wherein the shutter with the vertical bars includes an enlarged vertical bar at its upper right portion for blocking out the upper right indicator bar for displaying the numerals 5 and 6.

10. A digital display indicator as defined in claim 9 wherein a vertical bar is formed in the lower right portion of the vertical bar shutter inwardly from the bar formed at the upper right portion of the shutter for blocking out the lower right indicator bar for forming numeral 2.

11. A digital display indicator as defined in claim 1 wherein the shutter with the vertical bars includes a vertical bar at its upper left portion for blocking out the upper left indicator bar to display numerals l, 3 and 7.

12. A digital numeral display indicator as defined in claim 11 wherein a vertical bar is positioned inwardly from the vertical bar which is formed at the upper left portion of the shutter for blocking out the upper left indicator bar for forming numeral 2.

13. A digital display indicator as defined in claim 1 wherein the shutter with the horizontal bars includes an enlarged horizontal bar at its upper portion for blocking out the upper indicator bar to display the numeral l.

14. A digital display indicator as defined in claim 13 wherein an opaque shutter bar is positioned immediately below the upper horizontal shutter bar for blocking out the upper indicator bar for displaying the numeral 15. A digital display indicator as defined in claim 14 wherein an opaque shutter bar is positioned below the upper two horizontal shutter bars for blocking out the middle horizontal indicator bar to display a numeral 1.

16. A digital display indicator as defined in claim 15 wherein a fourth opaque horizontal shutter bar is positioned below the upper three horizontal shutter bars for blocking out the middle indicator bar to display the numeral 7.

17. A digital display indicator as defined in claim 1 wherein a lower most opaque horizontal shutter bar is formed in the horizontal bar shutter for blocking out the lower indicator bar for forming the numerals 4 and 7, and an opaque bar is positioned above the lower most shutter bar for blocking out the lower most indicator bar to display the numeral 1.

18. A digital display indicator as defined in claim 1 wherein the indicator member having the plurality of indicator bars is formed of a clear plastic material which is blocked out to reveal a clear numeral 8 unobstructed by any blocking out material at the corners of the numeral 8. 

1. A digital indicator for visually displaying numerals 0 thru 9 comprising: a. an indicator member having a plurality of indicator bars provided therein arranged in the shape of a figure 8, said indicator bars including three generally parallel horizontal bars, and two pairs of vertical bars on opposite sides of the horizontal bars: b. two movable shutters positioned adjacent to the indicator bars of said figure 8 member for selectively blocking out selected bars in order to selectively display numerals 0 thru 9; c. one of said shutters including a plurality of generally horizontal opaque bars for selectively Blocking out one or more of the three generally horizontal indicator bars, said horizontal bar shutter being arranged for movement up and down in a generally vertical direction behind said figure 8 member; and d. the other shutter including a plurality of generally vertical opaque bars for selectively blocking out one or more of the vertical indicator bars which are positioned on opposite sides of the horizontal bars, said generally vertical bar shutter being arranged for movement in a generally horizontal direction behind said figure 8 member.
 2. A digital numeral display indicator as defined in claim 1 wherein the horizontal and vertical indicator bar portions are formed as slots in an opaque plate with the slots extending through the plate from one side of the plate to the other side of the plate.
 3. A digital indicator as defined in claim 1 including: a. guide means for permitting slidable movement of said horizontal bar shutter in a generally vertical direction; b. guide means for permitting movement of said vertical bar shutter in a generally horizontal direction; c. a first lever operatively connected to said vertically movable shutter for moving the shutter; d. a second lever operatively connected to said horizontally movable shutter for moving the shutter; e. a rotatable cam having a front face and a rear face; f. a cam follower formed on said first lever for moving said vertically movable shutter; g. a cam follower formed on said second lever for moving said horizontally movable shutter; and h. cam tracks formed in the front and rear surfaces of said rotatable cam, one of the cam followers being positioned in one of the tracks for moving the horizontal shutter and the other cam follower being positioned in the other track for moving the vertical shutter, the cam track in the front surface of the cam being so related to the cam track in the rear surface of the cam so that in any one of a plurality of selected positions of said cam, the cam tracks and cam followers position the horizontal and vertical shutters to block out the appropriate indicator segments to display a numeral from 0 thru
 9. 4. A digital display indicator as set forth in claim 3 wherein the cam follower on the lever which is operatively connected to the horizontal bar shutter is positioned in the cam track formed on the front surface of the cam and the cam follower on the lever which is operatively connected to the vertical bar shutter is positioned in the track formed in the rear surface of the cam.
 5. A digital indicator as defined in claim 3 wherein the cam followers and the rotatable cam are formed of plastic material and the slope of the cam tracks vary from 0* thru 60* .
 6. A digital display indicator as defined in claim 1 wherein the shutters are made of a relatively thin transparent material, the opaque shutter bars are formed on the shutters, and a light source is positioned behind the shutters and the indicator bar member for illuminating the bars in the indicator member which are not blocked out by the shutters.
 7. A digital indicator as defined in claim 1 wherein the shutter with the vertical bars includes an enlarged vertical bar at its lower left portion for blocking out the lower left indicator bar in the indicator member for displaying numerals 1, 3, 4, 7 and
 9. 8. A digital indicator as defined in claim 7 wherein a vertical opaque bar is positioned inwardly from the vertical bar at the lower left portion of the shutter for blocking out the lower left indicator bar for displaying the numeral
 5. 9. A digital indicator as defined in claim 1 wherein the shutter with the vertical bars includes an enlarged vertical bar at its upper right portion for blocking out the upper right indicator bar for displaying the numerals 5 and
 6. 10. A digital display indicator as defined in claim 9 wherein a vertical bar is formed in the lower right portion of the vertical bar Shutter inwardly from the bar formed at the upper right portion of the shutter for blocking out the lower right indicator bar for forming numeral
 2. 11. A digital display indicator as defined in claim 1 wherein the shutter with the vertical bars includes a vertical bar at its upper left portion for blocking out the upper left indicator bar to display numerals 1, 3 and
 7. 12. A digital numeral display indicator as defined in claim 11 wherein a vertical bar is positioned inwardly from the vertical bar which is formed at the upper left portion of the shutter for blocking out the upper left indicator bar for forming numeral
 2. 13. A digital display indicator as defined in claim 1 wherein the shutter with the horizontal bars includes an enlarged horizontal bar at its upper portion for blocking out the upper indicator bar to display the numeral
 1. 14. A digital display indicator as defined in claim 13 wherein an opaque shutter bar is positioned immediately below the upper horizontal shutter bar for blocking out the upper indicator bar for displaying the numeral
 4. 15. A digital display indicator as defined in claim 14 wherein an opaque shutter bar is positioned below the upper two horizontal shutter bars for blocking out the middle horizontal indicator bar to display a numeral
 1. 16. A digital display indicator as defined in claim 15 wherein a fourth opaque horizontal shutter bar is positioned below the upper three horizontal shutter bars for blocking out the middle indicator bar to display the numeral
 7. 17. A digital display indicator as defined in claim 1 wherein a lower most opaque horizontal shutter bar is formed in the horizontal bar shutter for blocking out the lower indicator bar for forming the numerals 4 and 7, and an opaque bar is positioned above the lower most shutter bar for blocking out the lower most indicator bar to display the numeral
 1. 18. A digital display indicator as defined in claim 1 wherein the indicator member having the plurality of indicator bars is formed of a clear plastic material which is blocked out to reveal a clear numeral 8 unobstructed by any blocking out material at the corners of the numeral
 8. 